Jeremy Soller
17 lines
619 B
Rust
17 lines
619 B
Rust
use crate::acpi::ACPI_TABLE;
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use super::device::{hpet, pit};
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pub fn counter() -> u128 {
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if let Some(ref hpet) = *ACPI_TABLE.hpet.read() {
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let capability = unsafe { hpet.base_address.read_u64(hpet::CAPABILITY_OFFSET) };
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let period_fs = (capability >> 32) as u128;
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let counter = unsafe { hpet.base_address.read_u64(hpet::MAIN_COUNTER_OFFSET) };
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(counter as u128 * period_fs) / 1_000_000
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} else {
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// 1.193182 MHz PIT is approximately 838.095 nanoseconds
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let period_ns = 838;
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let counter = unsafe { pit::read() };
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counter as u128 * period_ns
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}
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}
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